they free up around 10 whp, but dont do undrives with it becuase your alternator wont have enough power when slowed down by the underdrives to power the pump and the rest of your car.

i have one but only becuase i got it new in the box used for less than half price

 

Interesting question.

The power to turn the water pump has to come from somewhere. Assuming the pump is turning as fast and is moving as much coolant then the total power drawn will be comparable. It's still ultimately a belt-driven accessory only now instead of driving the pump impeller directly you drive the alternator to generate the electricity to power the motor that drives the impeller. Neither the alternator nor the electric motor will have spectacular efficiencies so to get 'X' horsepower to move that impeller you need 1.3 (or more) * X horsepower going into the alternator.

Do you end up saving in the end? I'd have to see controlled experiments on dynos. I suspect that savings is coming from switching off the pump or running it at a reduced duty cycle during a dyno run, or for a run down the track or putting the pump on a thermostatic switch (e.g.) so it's not running all the time is probably where the majority of savings is seen. It's not unlike how electric fans are better than belt-driven fans, even ones with thermostatic hub clutches, because they only run when they're needed instead of all the time.

For a daily driver I suspect it's not worth it, sort of like UDPs...

 

The alternator doesnt cause more resistance when you go with an electric water pump. It still spins as if the waterpump were still belt driven. Youre overthinking this and its been prooven multiple times that goijg with electric it will free a couple ponies

 

The alternator doesnt cause more resistance when you go with an electric water pump. It still spins as if the waterpump were still belt driven.

Sorry, not buying the perpetual motion machine theory you're peddling.

Ever notice what happens to engine loading/speed at idle when you flip on a heavy electrical load like, say, a rear defogger grid? Or high beams? Or the blower motor on full? There is a definite increase in load and it's coming from the alternator.

When you put an electrical load on the alternator, its output drops. In order to compensate, the regulator adds field current. This results in higher stator (output) current but it also adds to the rotating resistance of the alternator because of the stronger magnetic fields. Bottom line: To get more electrical power out you need to feed in more mechanical power.

The alternator isn't just freewheeling, practically no-load all the time. The effort it takes to rotate it is proportional to the electrical demands being made of it. If you want to drive a 250W motor you're going to need to feed the alternator more than 250W of mechanical power; more, because the alternator is not 100% efficient at converting mechanical to electrical power; 80% is more typical. Then there's the motor's efficiency at turning electrical power into mechanical torque...expect only about 80% there too.

If you want to move coolant through the system at a given rate it doesn't matter if the pump is mechanically or electrically driven: the impeller still needs the same power input all else being equal. And that power needs to come from somewhere.

EWPs may save power if they are not being driven all the time (e.g. selectively turned off by the driver or by a thermostatic switch) or are being driven by, say, chopping (PWM) such that they spin slower than the mechanical belt-driven pump.

The EWP becoming a nearly load-less idler pulley versus a waterpump's drag caused by its seals is about the only other possible place to make a gain but I suspect it's likely a wash in the real world because you've removed a nearly 100%-efficient belt-drive in favor of mechanical-electrical-mechanical conversion where efficiencies might only get to about 80% at each stage.

Whether or not this makes sense for a daily driver and whether or not the bang/buck ratio is worth it is up the individual I guess. YMMV.

 

Kanuckistang, you are an idiot..



For one, you reduce parasitic drag by switching to an electric waterpump.
For 2, you get more efficient cooling typically because you no longer create and have to fight pressures caused at higher rpms.


Yes, your electric pump will draw a few more amps, and if your alternator can't handle the amperage, then you will see a voltage drop....same is to be said about your wiring...too small of wires and amperage goes way up and the alternator won't be able to keep up..

Just be sure to get a good pump and you will be fine..

I highly suggest you stay away from csr as everybody I know that has had one, has had multiple failures.

I use a meziere 55gph pump that has outlets to go to the heater system.


The only way you wont gain power is if you are already maxing out your electrical system.

You should see more consistent coolant temps and a better return to cooler temps after a run st the track..

The electric pump also allows you to circulate water with the pumps off, which means you can cool the engine while sitting still in the pits if you wire in a switch to it and the fans.

Electric pump wins hands down over a belt drive pump.

 

Actually the idiot is the guy who spends 400+ for 5-7 hp on a street car that you won't see until in the the higher rpm range. Which means rarely on the street. Either that or money is no object

 

LOL. And I doubt it's even 5-7HP.

And frankly, on a daily driver, I would want the rate of coolant circulation to increase with increasing engine speed...

To each his own.

 

Alright, well all of that answered my question! lol. Thanks for the input guys! Doesn't seem like its all worth it.

 

Yes, an electric water pump is worth hp. It has been proven time and time again on the dyno. One that comes to mind is an article in MM&FF, November 2006 on project red headed step child picked 14 hp. To be fair that was without an accessory belt. So let's cut that nearly in half and say 8 hp to the wheels with a belt. I would guess the pump to be worth at least 10 hp at the crank. I have a meziere pump that I recently put on and I will post et results when I hit the track again.

 

I have a meziere pump that I recently put on and I will post et results when I hit the track again.

Thats the pump I was looking at, the 55g.

 

It was one of the easiest and quickest mods I have done. I am completely maxed out on bolt ons with the pump installed. If a person is considering it I say go for it, but it doesn't have to be one of their first mods.

 

Its a safer mod than an underdrive pulley...
Underdrive pulleys spin accessories slower by using a smaller Crank pulley, which is bad for your crank dampening...smaller pulley means more internal engine vibration.

changing to an electric pump, frees up the parasitic loss without affecting the damping power of the larger crank pulley.

 

I loved my Aerospace EWP. Was worth a tenth over an undrive pulley setup. It was idlerless though so I'm sure that was worth a hp or two over the mezerie setup. The cool part about it was that I could bypass the PS pump if desired at the track or completly remove the belt and gain an additional .15 at the track.